ADS-B

ADS-B has two sides: ADS-B Out (transmitting your position to others) and ADS-B In (receiving traffic and weather from others). ADS-B Out has been required in most controlled airspace in the US since January 2020. ADS-B In is optional but adds a lot to situational awareness.

Aircraft with ADS-B In can show nearby traffic and weather on an IFD or compatible tablet. If you see ADS-B in a school's aircraft specs, that generally means the avionics are relatively current.